Question

In 2004, U.S. landfills emitted approximately 6,709 Gg of methane emissions and wastewatertreatment plants emitted 1,758 Gg of methane. How many Tg of CO2 equivalents did landfills and wastewaterplants emit in 2004? What percent of the total 2004 methane emissions (and greenhouse gas emissions) do these two sources contribute (total methane emissions in 2004 were 556.7 Tg CO2e and total greenhouse gasemissions in 2004 were 7,074.4 TgCO2e)

Answer 1

1 Gg= 10⁹ gms

Total grams of methane= (6709+1758)Gg=8467 Gg=8467*10⁹ gms

The reactions is CH4+ 2O2---> CO2 + 2H2O

Molecular weight of CH4= 16 and that of CO2= 44

16gms gives 44 gms of CO2 ( 1 mole of CH4 gives 1 moles of CO2)

8467*10⁹ gms gives 8467*10⁹*44/16=2.33*10¹³ gms of CO2

10¹² gms =1 Tg

Tg of CO2= 2.33*10¹³/10¹²= 23.3 Tg of CO2

Conribution of these emissions to total methane emission =100* (23.3/556.7)=4.11%

Contribution to green house emissons = 100*23.3/7074.4=0.33%